The invention relates to an electromagnetically actuatable proportional valve, in particular a differential pressure valve for use in CO2 air conditioner compressor arrangements, comprising an electromagnetic actuator for adjusting a valve body relative to a valve seat, wherein the valve seat is assigned a first pressure connection via which a fluid can bypass the valve body and flow to a second pressure connection. The invention, furthermore, relates to an air conditioner compressor arrangement (air conditioning system), in particular in a motor vehicle, and to a method for operating an electromagnetically actuated proportional valve and/or an air conditioner compressor arrangement.
From EP 1 628 017 A2 and EP 1 098 091 B1 proportional valves for air conditioner compressor arrangements in motor vehicles designed as differential pressure valves are known. The known proportional valves serve for regulating the cooling output of the compressor (air conditioner compressor) which is directly coupled to a motor vehicle drive motor via a belt. By means of an electromagnetic actuator, a valve body formed as valve sphere in the case of the device known from EP 1 628 017 A1 and as valve plunger in the case of the device known from EP 1 098 091 B1 is adjustable relative to a valve seat assigned to a high pressure connection (compressor delivery pressure connection). With both known proportional valves, the valve body, when lying against the valve seat, closes the fluid connection between the aforementioned high pressure connection and a crankshaft pressure connection having a lower pressure in a fluid-tight manner. Thus, the full fluid pressure present at the high pressure connection acts on the valve body which for closing the proportional valve or the high pressure connection has to be overcome by the electromagnetic actuator.
The comparatively large magnetic force that is required in order to adjust the valve body relative to the valve seat is considered disadvantageous with the known differential pressure valves. In the known designs, this results in comparatively large coil arrangements and large armatures, as a result of which altogether an installation space is required that is not available in any size for motor vehicle applications. The moving load of the armature, of necessity, is comparatively large as well which leads to corresponding disadvantages of a large moving load.